Some golfers desire a golf club that they can personalize to their playing style. For example, increasing heel or toe-weighting can help correct for a hook or a slice. However, adjustable golf clubs are fraught with problems. The adjustment mechanisms interfere with golf club aerodynamics and also trap soil or other environmental grime. Also, since the adjustment mechanisms can be fragile, they can break during golf. Additionally, the adjustment mechanisms add undesirable mass to the club head.
Some attempts have been made to move the mechanisms to the interior of the golf club. For example, U.S. Pat. No. 8,206,243 to Stites describes a club head with movable weight members contained internally. Unfortunately, the removable crown part for accessing the weight members may not cope with stress well. During a powerful drive, the crown may crack or pop off of the club head, causing great frustration to the golfer. It may be found that the removable crown—having much less structural support than the material of the body surrounding the crown—deforms differently than the body and flexes out of shape relative to the body, leading to rapid failures. Also, some removable body part designs such as shown in U.S. Pat. No. 8,435,135 to Stites do not really open up a hollow club head, but simply add a component on top of a fully enclosed part of a club head, or they only provide very limited access to the interior of the club head (e.g., U.S. Pub. 2010/0160091 to Boyd).